Following is the grading of severity of thyroid disease. 0 – No symptoms and findings 1 – No signs and symptoms, spasm in the upper eyelid with increased eye opening 2 – Swelling in the preorbital soft tissue, other sign and symptoms appear 3 – Ptosis or exophthalmos ( > 20 mm) 4 – Extraocular muscle involvement 5 – Corneal involvement 6 – Involvement of optic nerve, loss of vision at several levels ( visual acuity < 0.67)